VENUS. 399 



Abroad it has its chief centre in the Lusitanian Province, 

 and is abnndant in the Mediterranean. It was an inhabit- 

 ant of onr seas as long ago as the epoch of the coralHne 

 crag but retired southwards during the prevalence of glacial 

 conditions, and afterwards returned. 



SPURIOUS. 

 C. ciRciNATA, Born. 



Venus circinata. Born, Mus. Cpgs. Vindol). p. Gl, pi. 4, f. o. — Ciiemn. Concli. 



Cab. vol. vi. p. 312, pi. 30, f. 311.— Dillw. Recent Shells, 



vol. i. p. 1()9, 

 Venus Gtiineetisis, Gmelin, Syst. Nat. p. 3270. — Mont. Test. Brit. Siippl. pp. 



48, 1G8 Dorset Catalog, p. 35. — Turt. Conch. Diction. 



p. 237. 

 Cylherea Guiiieensis, Lam. Anira. s. Vert. (ed. Desli.) vol. vi. p. 311. — Turt. 

 Dithyra. Brit. p. 161. — Flem. Bnt. Anim. p. 445. — 

 Brit. Marine Conch, p. 84.— Hanl. Recent Shells, p. 100. 

 Encyclop. Method. Vers. pi. 265, f. 1. 



Inhabits the S. Atlantic Ocean ; ivas introduced by Montagu, as 

 taken in the Frith of Forth by Mr. Lashey, 



VENUS, Linn^us. 



Shell often thick, equivalve, closed, more or less subor- 

 bicular or transversely ovate, generally ornamented by con- 

 centric ribs or strise, in some species decussated by longi- 

 tudinal furrows, often brightly coloured. Margin erenated. 

 Beaks prominent. Hinge composed in each valve of three 

 diverging cardinal teeth. Ligament strong, external, 

 lodged in a well-defined area. Lunule well-marked. Mus- 

 cular impressions rounded, strongly marked, Pallial sinus 

 lanceolate, wide. 



Animal ovate or suborbicular, thick ; its mantle open 

 throughout, and fringed or furbelowed at the margins. 

 Siphons separate, and diverging, or partially, or even en- 



